H˘j˘ Tokimasa was a valued ally of Minamoto Yoritomo from the latterĺs
days as an exile in Izu, when he married Tokimasaĺs daughter Masako.
Tokimasa joined Yoritomo in declaring war on the Taira family in 1180 and served
on his Kamakura headquarters for the duration of the war. After the Taira defeat
in 1185, Tokimasa was sent to present a request to the Imperial Court that
supposedly resulted in the first appointments of Shugo and jitō.
The H˘j˘, led by Tokimasa and the influential Masako, had become one of the
most powerful families in Kamakura when Yoritomo was named Shogun in 1192.

When Yoritomo died in 1199 Tokimasaĺs grandson Yoriie became the new shogun,
although the greatest influence on the young man was actually Hiki Yoshikazu,
Yoriieĺs father-in-law and guardian. Yoriie was a difficult man, and developed a
dislike for the H˘j˘, at the same time damaging his own position through his
youthful thoughtlessness. When a council was formed among the chief Bakufu
retainers to moderate Yoriieĺs judicial authority, Yoriie responded by turning
on the man regarded as his most outspoken opponent, governor of Sagami Kajiwara Kagetoki.
Although Kajiwara had been one of Yoritiomoĺs most trusted retainers, he was
hunted down and killed in Suruga by Bakufu troops in 1200. Tokimasaĺs role in
the downfall of Kajiwara is unclear, but his clan did benefit from the event by
acquiring the now open province of Sagami. Kajiwaraĺs death also had the effect
of tidying the political playing field in Kamakura, leaving the Hiki as the next
major obstacle to Tokimasaĺs ambitions. Knowing that there was little hope of
supplanting Hiki at Yoriieĺs side, Tokimasa placed his political capital on
Minamoto Sanetomo, Yoriieĺs younger brother. In 1203 Yoriie became very ill, and
the H˘j˘ pushed through a plan that would divide the realm between Sanetomo and
Yoriieĺs son Ichiman. The Hiki Yoshikazu doubt guessed Tokimasaĺs ploy, and
plotted to have the H˘j˘ leader murdered. Tokimasa in turn caught wind of the
danger he was in, and after consulting Ōe Hiromoto, made a preemptive strike. He
invited Yoshikazu to his residence ostensibly for Buddhist services, and when
Hiki unwisely came out H˘j˘ had the man murdered. H˘j˘ retainers and allies then
descended on the Hiki residence and killed Ichiman and most of the Hikiĺs
important names, thus eliminating the Hiki in one decisive stroke. With his most
powerful political supporter gone, Yoriie was isolated and within a few weeks
stepped down from office. He went to live at the Shuzenji in izu and was
murdered a year later-probably on the order of Tokimasa.

Tokimasa installed Sanemoto as the 3rd Minamoto Shogun and began
to exercise control through the Mandokoro, which he chaired along with Ōe
Hiromoto. The most powerful man in Kamakura, Tokimasa was known as the
shikken, a term that at the time referred to his position on the
mandokoro. Later, shikken would come to refer to the role the H˘j˘
clan played in Bakufu politics - that of regents to a series of child-shoguns.

Ironically, Tokimasa may in the end have schemed once too often. In 1204, a
certain Hiraga Tomomasa convinced Tokimasa that Hatakeyama Shigetada, Tokimasaĺs
son-in-law, was engaged in treasonous behavior. Tokimasa ordered his sons
Yoshitoki and Tokifusa to kill Hatakeyama, over Yoshitokiĺs objections.
Hatakeyama was duly executed, but with a resentful Yoshitoki still convinced of
his innocence. That Shigetada just so happened to be another potential rival to
the H˘j˘ stranglehold on Kamakura politics likely had more to do with his death
than any treasonous ideations.

Some time after the Hatakeyama affair, in 1205,Yoshitoki heard rumors that
Tokimasa was planning to have Sanetomo assassinated and replaced with none other
then Hiraga Tomomasa, a man of Minamoto stock. Yoshitoki and Masako, who also
seems to have drawn away from her father, took steps to foil the scheme by
putting Sanetomo under guard and killing Hiraga. Yoshitoki openly challenged his
fatherĺs authority, and left Tokimasa little choice but to step down. Tokimasa
shaved his head and departed for exile in Izu province, his political career at
an end. Whether or not Tokimasa really intended to have Sanetomo killed is
anyoneĺs guess. Sanetomo was hardly a difficult character - most of his time was
spent studying the arts - in particular poetry. Possibly Tokimasa had become a
liability to Masako and Yoshitoki - we have no way of knowing. That Tokimasaĺs
career had a profound effect on the course of Japanese history is somewhat more
obvious.